Diffusion transfer materials and process with derivatives of 4-amino-1,2,4-triazoline-5-thione as toning agents

ABSTRACT

A DIFFUSION TRANSFER IMAGE HAVING DENSELY BLACK IMAGE TONE IS PRODUCED BY EFFECTING DEVELOPMENT AND DIFFUSION IN THE PRESENCE OF 4-AMINO-1,2,4-TRIAZOLINE-5-THIONE DERIVATIVES. THE EXAMPLES OF SAID DERIVATIVES ARE 4-AMINO-3ETHYL - 1,2,4- TRIAZOLINE-5-THIONE, 4-AMINO-3-PROPYL-1,2,4TRIAZOLINE-5&#39;&#39;-THIONE, ETC.

United States Patent 3,576,629 DIFFUSION TRANSFER MATERIALS AND PROC-ESS WITH DERIVATIVES 0F 4-AMINO-1,2,4-TRI- AZOLINE-S-THIONE AS TONINGAGENTS Kiyoshi Futaki and Noboru Itoh, Kyoto, Sendgi Tosa,

Osaka, and Hirokazu Tsukahara, Kyoto, Japan, assignors to MitsubishiPaper Mills, Ltd., Tokyo, Japan No Drawing. Filed Mar. 11, 1968, Ser.No. 711,880 Claims priority, application Japan, Mar. 27, 1967, 42/18,646 Int. Cl. G03c 5/54 US. Cl. 96-29 5 Claims ABSTRACT OF THEDISCLOSURE A diflusion transfer image having densely black image tone isproduced by effecting development and diffusion in the presence of4-amino-1,2,4-triazoline-5-thione derivatives. The examples of saidderivatives are 4-amino-3- ethyl 1,2,4- triazoline-S-thione, 4amino-3-propyl-1,2,4- triazoline-S-thione, etc.

This invention relates to an improved photographic silver complexdiffusion transfer process for obtaining dif fuion transfer imagespossessing a densely black image tone and a developer and a photographicmaterial used for said process.

The principle of the silver complex diffusion transfer process can bebriefly described as follows: a light-sensitive silver halide emulsionlayer which is coated on a basesheet such as paper or plastic film isimagewise exposed and thereupon pressed into contact with animage-receiving layer which is coated with colloidal dispersion of aheavy metal or metal sulfide immersed in a hydrophillic binder such asgelatin or polyvinyl-alcohol, in the presence of a developing agent anda complexing agent for silver halide. The exposed silver halide grainsare developed to metallic silver images and do not undergo any furtherchange, while the unexposed part of the light-sensitive lay er iscomplexed with a complexing agent such as a thiosulfate, a sulfite or anorganic amine which is present either in the developer or in theimage-receiving layer, where it is converted into metallic silver imageby means of colloidal metallic particles which act as developing nucleiduring development. In such a way, a positive image of the originalappears in the image receiving layer after separating the latter fromthe light-sensitive layer.

One of the most serious defects of the silver complex diffusion transferprocesses in the early stage of progress of this process is thedisagreeable brown or yellowish image-tone of the final positive images,and it was necessary to use a goldor selenium toning to change the colorto neutral-black or pleasant sepia-black by after-treatments, andrecently it was found that the introduction of some sorts of substancesuch as mercapto-benzothiazole, benzotriazole,phenyl-mercapto-tetrazole, usually known as antifoggant or blue-blacktoner in an usual photographic silver halide emulsion layer, could alsochange the tone of image-color of a receiving layer from brown toneutralor blue-black.

These organic heterocyclic compounds, however, usually make sparinglysoluble complexes with silver halide and accordingly tend to decreaseboth the rate of development in an sensitive layer and the rate ofimage-formation in a receiving layer, and it was difiicult to obtain auseful or- 3,576,629 Patented Apr. 27, 1971 ganic toner which does notprolong the developing and transfer time and makes neutral black imageof sufficiently density.

And it was a usual practice to combine these developing-retardingblue-black toners such as benzotriazole, 5- nitro-benzimidazole orphenyl-mercapto-tetrazole with some of the substances which are known asan accelerator for developer, such as benzylamine, fi-phenyl-ethylamineand N-dodecylpyridinium salt, because these accelerators usually havenot effect or sometimes adverse effects on the image color.

Recently some substances which having blue-black toning effect uponimage color, and can accelerate the process, were found. They are, forexamples, 2-alkyl-l,3,4- oxadiazolin 5 thiones or 3alkyl-benzoXazoline-2- thiones (Phot. Sci. & Eng. 4, 257-263 (1960)) andin patent-literatures other thiol compounds such as 5,5- dimethyl 4thio-hydantoin, S-benzilidene-1,3-oxazo1idine 4 on 2 thione or 5 methyl3 mercapto-1,2,'4- triazole.

These compounds usually called as blue-black toner, are not so effectivewith emulsions composed mainly silver chloride, and lose the toningeffect by the presence of these silver complexing agents asthiosulfates, which make soluble complex with silver halide, in thedeveloping solution.

Much efforts have been made by the inventors to obtain a useful blueblack toners which can accelerate the rate of development even in thesilver complex diffusion transfer processes which use a developercontaining thiosulfates. It was found at first that4-amino-1,2,4-triazoline-5-thione has a remarkable accelerating effecton the image formation in an image-receiving layer, yet unfortunatelyhas little effect as a blue-black toner. After investigating a greatnumber of compounds, two series of the derivatives of this compoundhaving the following general formulas (A and B) were found to possessexcellent properties not only to give dense-black or b1ue-black transferimages but also to accelerate the image formation in a silver complexdiffusion transfer process;

wherein R represents a hydrogen atom or one of lower alkyl, aryl andaralkyl groups and R represents a lower alkyl group. Substances of Bseries are N-acyl derivatives of A.

Considerable differences are found between the characteristics of theabove-mentioned two series of derivatives. All of the first mentioned Aseries show a remarkable development-accelerating effect, but atone-modifying effect varies with the number of carbon atoms in R Whilethe effect being influenced by changes of conditions such asconcentrations of the agent, contents of thiosulfates, kinds of halogenin the silver halide grains, dimensions of grains in the emulsion,temperature, usually the tone-modifying effect tends to be enhancedinitially with the increase of carbon atoms in R and after reachingmaximum tends to fall off at a certain number of carbon atoms in R (seeExample 2).

The derivatives of B series, on the other hand, show little developingretarding effect compared with the wellknown blue-black toners, canhardly show any tendency to accelerate the process and rather tends toretard it with increase of the carbon atoms in R and R These compounds,however, have very excellent blue-black toning or tone-modifyingeffects, which tends to be lower with the increase of carbon atoms in Rand R So it is clear that some of the compounds of both series havinglower alkyl, aryl or aralgyl substituents, alone can be an excellenttoner in themselves, compared with usual known compounds; but the abovementioned characteristics of the two series of compounds are mutuallycomplemented and using both series of compounds in combination mayresult in high effects which cannot be obtained using the compoundalone, and the compounds which have rather low utility when used alonecan easily exhibit more excellent effects than any other known additivesby being used jointly.

Any compounds of these two series can be used in combination with someof the known toning agents for the purpose of obtaining furtherpractical merits.

The typical derivatives of A series include4-amino-3-methyl-1,2,4-triazoline-5-thione,4-amino-3-ethy1-1,2,4-triazoline-S-thione,4-amino-3-propyl-1,2,4-triazoline-S-thione,4-amino-3-butyl-1,2,4-triazoline-5-thione, 4-amino-3-p-tolyl-1,2,4-triazoline- -thione,

4-amino-3 -p-methoxyphenyl- 1 ,2,4-triazoline-5-thione,4-amino-3-p-chlorobenzyl-1,2,4-triazoline-5-thione, etc.

The typical derivatives of B series include4-acetamide-1,2,4-triazoline-5-thione,4-acetamide-3-methyl-1,2,4-triazoline-5-thione,4-acetamide-3-ethyll,2,4-triazoline-5-thione,4-acetamide-3-propyl-1,2,4-triazoline-S-thione,4-acetamide-3-butyl-1,2,4-triazoline-S-thione,4-ethylamide-3-methyl-1,2,4-triazoline-5-thione, 4-ethylamide-3-ethyll,2,4-triazoline-5-thione,4-ethylamide-3-propyl-1,2,4-triazoline-5-thione,3-methyl-4-pyropylamide- 1,2,4-triaZoline-5-thione,3-ethyl-4-propylamide-1,2,4-triazoline-5-thione,4-butylamide-3-methyl1,2,4-triazoline-5-thione,4-acetamide-3-phenyl-1,2,4-triazoline-S-thione,4-acetamide-3-p-chlorophenyl-1,2,4-triazoline-5-thione,4-acetamide-3-p-tolyl-1,2,4-triazoline-5-thione,4-acetamide-3-benzyl-1,2,4-triazoline-S-thione, 4-propylamide-3-p-chlorobenzyl-1,2,4-triazoline-5- thione,4-acetamide-3-phenethyl-1,2,4-triazoline-5-thione,4-acetamide-3-p-n1ethoxybenzyl-1,2,4-triazoline-5- thione, etc.

They can be added in the developer solution, but ususally it isfavourable to introduce them into the receiving layer (or the over-layerupon it) or the sensitive layer (or the over-layer upon it), because thetoner or toners in these layers diffuse out into the developer which areapplied between the layers during the process.

The required concentration of the toner Widely varies according tovarious factors involved in the system, such as temperature, contents ofthiosulfate in the developer, etc. as mentioned above, but probably liesin a range between 0.01 to g./l. in the developer and 0.01 to 0.1 g./m.in the image-receiving layer or the light-sensitive layer, as a totalsum of the agents used alone or in combination with similar compounds.

Compounds of this invention are soluble in an aqueous alkaline solutionand are very stable in a solution of caustic alkalin. The properties aresuitable to be added in a developer of the silver complex diffusiontransfer system. The elfects are not influenced very much by thetemperature of developer, but it is favourable to carry out thedevelopment at a temperature between C. and 35 C., considering the rateof diffusion of the silver complexes in the layer.

The derivatives of 4 amino-1,2,4-triazoline-5-thione show a Tautomerismas follows:

The compounds of this invention can be prepared as schematicallydescribed below:

4-acetamido-3-ethyl 1,2,4 triazoline-S-thione, for example, can beprepared as follows: 106 grams of thiocarbohydrazide and 222 grams ofpropionic acid are mixed and heated for 9 hours at a temperature of 140to 150 C. to yield 86 grams (60% of the theoretical amount)4-amino-3-ethyl-1,2,4-triazoline 5 thione (M.P. 149- 150 C.), whereupon72 grams of the latter compound is dissolved in 100 ml. acetic anhydrideand the solution is heated for 3 hours at a temperature of to C., thencooled and resulting crystals are dissolved in an aqueous solution ofsodium hydroxide. Acidification of the alkaline solution to a pH value 5by adding hydrochloric acid gives 35 grams of colourless crystals (M.P.202-203 C.). Other derivatives can also be prepared in a similar mannerwith ease.

EXAMPLE 1 A light-sensitive materialwas prepared by coating a papersupport with a silver chloride-gelatin emulsion of low sensitivity.

An image-receiving material was prepared by coating a paper support witha suspension from the following coating composition:

Water4 l.

Gelatin g.

Polyvinylalcohol-60 g.

3% solution of copolyvinyl-methylether-maleic anhydride in water (pH isadjusted to 6.0)1 l.

1% colloidal dispersion of cadmium sulfide in Water-60 ml.

Coating weights of the suspension was adjusted to about 40 to 60g./sq.m. And after drying precoating, a protective coating of 1.5%solution of sodium carboxymethylcellulose in water (about 30 g./m. wasapplied over the coating.

A light-sensitive paper was exposed image-Wise, while being in contactwith an original to be reproduced, whereupon it was passed together withthe above image-receiving material through a developing bath of thefollowing composition:

Hydroquinone 12 1-phenyl-3-pyrazolidone 1 Anhydrous sodium sulfite 60Sodium hydroxide 12 Potassium bromide 1.5 Sodium thiosulfate 104-amino-3-propyl-1,2,4 triazoline-S-thione 0.3

Water up to 1 l.

When leaving the developing bath, both materials are pressed togetherand then, after a contact period of one to five seconds, separated fromeach other. An image with completely dense black tone was obtained inthe present image-receiving layer. When the same amounts of4-amino-1,2,4-triazoline--thione was used instead of the above-mentioned3-propyl derivative, the diffusion rate of the silver complex was sorapid as well, but the image-tone was rather brown and unfavourable.Without these compounds, 30 to 60 seconds of a contact period wereneeded to obtain an image of an unfavourably yellowish brown tone on thesame image-receiving layer.

EXAMPLE 2 The table below shows the colour-ratio, defined as the ratioof the reflection density measured at 400 m to that at 700 m of atransferred image on an image-receiving material obtained by thediffusion transfer process using developers which consist of almost thesame components described in Example 1 and using various toning agent of4-amino-1,2,4 triazoline-S-thione derivatives. The imagetone isgenerally represented by the colour-ratio, and the image-tone was brownor brownish black when the colourratio was larger than two, and it wasneutral black or blue-black when it was smaller than two on thecontrary.

TABLE OF COLOUR-RAIIO 1-phenyl-3-pyrazolidonel g. Anhydrous sodiumsulfite70 g. Sodium hydroxide-15 g. Sodium thiosulfate4 g. Potassiumbromide2 g.

EXAMPLE 4 The coating solution for the protective layer of theimage-receiving material described in the Example 3 was further added to5 ml. of 1% solution of Z-methyl-S-mercapto-1,3,4-triazol, a well knowntoning agent, in ethanol, and the amount of 1% solution of4-propion-amido-3- methyl-1,2,4-triazoline-5-thione in ethanol wasreduced to 2 ml. Thus, the combination of two or more toning agentsleads to a wide latitude for the processing conditions such astemperature, and also serves to the reduction of the cost of material.

It is often more favourable to add the second toning agents into thelight-sensitive layer as in the case of the Example 3. But, whenhydrazines or amines are incorporated as an accelerator, it isfavourable to add a toning agent into the developer as in the case ofthe Example 1.

EXAMPLE 5 On the surface of the film base made of 0.05 mm. thin H --CHCzH5 CaH1 C4Hn -CsHn pH -C1H15 A 4.7 2.3 1 6 1.5 2.9 4.4 3.9 B {CH 2. 22. O 1 9 2. 2 2. 3 2. 8 3. 9 R C H 0. 9 1 2 1. 4 1. 6 2. 2 1 9 2. 5 z{Ph 2.7 2 7 3.0 3.3 3.6 3.8 CH Ph 3.2 3 O 3.2 3.6 3.3 3.1 3.8

NOTE .Ph means a phenyl group.

The above table demonstrates the effect of carbonnumbers of substituentsupon the image-tone, and clearly indicates that the derivatives of Bseries have only poor effect, and they are excluded from our invention.

EXAMPLE 3 0.01 gram l-phenyl-S-mercapto-1,2,3,4-tetrazole and 0.01 grammercapto-benzothiazole were added per litre of the emulsion described inthe Example 1. They are well known stabilizing agents.

An image-receiving material was also prepared by coating a paper supportwith a suspension of the coating composition described in the Example 1(coating weight: 40 to 60 g./m.

After drying there was applied over the coating a further solution ofthe following composition as a protective layer. (about 30 g./m.

Waterl l. Hydroquinone-10 g.

polyethylene terephthalate subbed already for the coating ofphotographic emulsion by the method well known in the art or by themethod described in US. Pat. 3,214,274, an image receiving layer wascoated (about 50 g./m. from the following coating composition:

Water7 l.

Gelatin120 g.

Polyvinylalcohol120 g.

Copolymer of vinyl methyl ether and maleic anhydride40 g.

Half amide of the above mentioned polymer20 g.

1% colloidal dispersion of cadmium chloride waterml.

Over the coating an inter-layer of the following composition was coated(about 30 g./m.

Polyvinyl pyrrolidone-30 g.

Water-1 1.

10% solution of polyacrylamide (in water)l00 ml. Decolourable dyestuif(brown colour)2 g.

5% solution of saponin (in water)-200 ml.

After drying, silver-chloro-bromide gelatin emulsion, of which about ahalf amount of gelatin was displaced by the same amount ofcarboxy-methyl-starch and also added with 0.02 g./l. of benzotriazole asstabilizer, was coated on the inter-layer and finally 2% solution ofcarboxy methyl-starch was over coated as a protective layer.

The photosensitive material thus produced was particularly suitable forretrievals of the drawings for industrial design or architecture from amicro-filmed positive, and also suitable for obtaininginter-diapositives of medium size from original drawings by directcameracopying.

After exposure by camera or enlarger, the sensitive material wasprocessed for 30 sec. to 1 min. in the transfer-developer of thefollowing composition;

G. l-phenyl-3-pyrazolidone 1.0 Sodium sulfite anhydrous 75. Hydroquinone10.0 Caustic soda 15.0 Sodium thiosulfate 30.0 Potassium bromide 2.04-amino-3-propyl-1,2,4-triazoline-5-thione 0.06

4-acetamido-3-methyl-l,2,4-triazoline-5-thione 0.04 Water up to 1 1.

During processing, a negative image Was produced in an upperlight-sensitive layer and a positive image was transferred into thelower image-receiving layer by diffusiontransfer process at the sametime, then the material was transferred to the washing bath, where theupper layer was dispersed into water by means of the inter-layer whichmay be easily disintegrated into solution, and there left a finalpositive image on the film base in a very short time.

As fixing is not necessary in this operation, after a short rinse, afterthe film is treated by an acidic methanol solution, it will be quicklydried to get a positive picture consisted of a dense black lines anddots on a transparent film base.

EXAMPLE 6 60 m1. of 1% solution of4-amino-3-propyl-1,2,4-triazoline-S-thione in ethanol plus 40 ml. of 1%solution of 4-acetamido-3-methyl-1,2,4-triazoline-5-thione in ethanolwere advantageously added to the coating solution for theimage-receiving layer described in the Example 5, instead of being addedinto the developer. In contrast with this, benztriazole was added intothe developer instead of being added into the photo sensitive emulsion,but the latter case was disadvantageous, considering the stability ofthe photo sensitive materials.

EXAMPLE 7 0.07 g. of 4-acetamide-3-ethy1-1,2,4-triazoline-5-thione per 1l. of emulsion was contained in the sensitive layer of Example 1. Thesame image-receiving material as in Example was prepared. A positivedensely black image was immediately formed on the image-receivingmaterial using the usual developing solution for the silver complexdiffusion transfer process.

EXAMPLE 8 A sensitive material was prepared by coating the support paperof 90 g./m. with gelatino-silver halide emulsion in such a way that 1.30g. of silver chloride was present per 1 m? of the sensitive material. Asensitive sheet was produced by coating the following solution on saidemulsion layer at the rate of 1 l./ 10 m2.

PAM75 (trade name for polyacrylamide having a medium viscosity andproduced by American Cyanamide Company)l g.

% solution of saponin10 cc.

4-amino-3-ethyl-l,2,4-triaz0line-5thione0.08 g.

Water1000 cc.

The image-receiving material was produced by coating the followingsolution on a support paper of 80 g./m. at the rate of 35 g./m.

Gelatin-10 g.

Barium sulfate-350 g. Cobalt sulfide-08 g. Sodium thiosulfatel00 g.

1% ethanol solution of 1 phenyl 5 mercapto-tetrazole25 cc. Watercc.

A positive densely black image was immediately formed on theimage-receiving material using the treating solution of Example 3 as thedeveloping solution.

What we claim is:

1. In a photographic silver complex diffusion transfer process, theimprovement which comprises effecting development and diffusion in thepresence of at least one 4-amino-1,2,4-triazoline-S-thione derivative ofthe general formula:

wherein R is a member selected from the group consisting of hydrogen,lower alkyl, aryl and aralkyl, and

X is a member selected from the group consisting of NH and NHCOR whereinR is a lower alkyl group, said process immediately producing a denselyblack transfer image.

2. The improved photographic silver complex diffusion transfer processaccording to claim 1, in which 4-amino- 1,2,4-triazoline-5-thionederivatives used are selected from the group consisting of4-amino-3-ethyl-1,2,4-triazoline-5- thioue, 4-amino 3propyl-1,2,4-triazoline-5-thione, 4- ethylamide 3methyl-1,2,4-triazoline-S-thione,4-ethylamide-3-ethyl-1,2,4-triazoline-5-thione and 4-ethylamide-3-propyl-1,2,4-triazoline-5-thione.

3. In a developer for immediately producing diffusion transfer imagescomprising a silver halide solvent and at least one developing agent,

the improvement wherein said developer contains at least one4-amino-1,2,4-triazoline-5-thione derivative of the general formula:

R C--NX ll :8

wherein R is a member selected from the group consisting of hydrogen,lower alkyl, aryl and aralkyl,

X is a member selected from the group consisting of NH and NHCOR whereinR is a lower alkyl group, wherein said transfer images possess a denselyblack image tone.

4. A silver complex diffusion transferring material containing at leastone of the derivatives according to claim 3 in an image-receivingmaterial.

5. A silver complex diffusion transferring material containing at leastone of the derivatives according to claim 3 in a sensitive layer or alayer adjacent thereto.

References Cited UNITED STATES PATENTS 3,017,270 1/1962 Tregillus et al.96--29 3,335,009 8/1967 Rasch et al 966l 3,232,759 2/1966 White et al.96-29 OTHER REFERENCES Hoggarth, J. Chemical Soc., 1952, pp. 4811-4817.

NORMAN G. TORCHIN, Primary Examiner W. H. LOUIE, IR., Assistant ExaminerUS. Cl. X.R. 96-52

